1. Field of the Invention:
The present invention relates to a projectile delivery apparatus and more particularly to such an apparatus which imparts improved penetration characteristics to a projectile so delivered to a preselected target, the apparatus enclosing the projectile in a friable capsule, and adapted to traverse the distance from the firearm to the target while retaining the launch weight of the projectile intact.
2. Description of the Prior Art:
Weapons development, and more particularly the development of improved projectiles which are adapted to penetrate hardened targets composed of a variety of different compositions for the purpose of destroying, or otherwise disabling the target to achieve military or police objectives has long been an extremely fertile area for research and development activity.
There are a variety of tactical situations where police and military personnel must, from time to time, utilize variously designed projectiles against a hardened target. When these situations develop, the projectile of choice can change from one instance to the next, due in part to a fluid tactical environment, or the need to engage assorted targets at ever changing distances. It should be understood that the selection of the wrong projectile can potentially jeopardize the success of any operation undertaken. For example, an armor piercing projectile may be utilized for purposes of disabling a vehicle, or alternatively may be used to penetrate a hardened target to disable an assailant. The prior art devices designed for such purposes have suffered from several chronic problems which have prevented their being utilized except in very narrow circumstances. It is well known, for example, that commercially available armor piercing projectiles have significant range and therefore should not be employed in a built-up environment where the projectile could perhaps pass through the hardened target and continue on into areas where innocent bystanders may be present.
In light of the shortcomings recognized in commercially available armor piercing projectiles, police and special forces military units have sought after a projectile for use in a close assault weapon which is capable of penetrating hardened targets, but similarly does not have the deleterious characteristic of propelling the projectile for significant distances. This feature is highly desirable in those tactical situations where the target to be engaged is near by, for example, in distances of 100 yards or less. Heretofore, the close assault weapon of choice for engaging personnel targets in short distances has been the shotgun. Typically, double aught buck (00) rounds are employed for this purpose.
Although a shotgun utilizing a double aught buck round is highly effective against personnel targets, its ability to penetrate a hardened target is quite limited. The inability of a double aught buck round to penetrate a hardened target is influenced by numerous factors, including a multiplicity of aerodynamic forces which act on the projectile itself.
Of the numerous aerodynamic forces acting on a projectile which is fired from a weapon, one which is always present is drag, or air resistance to forward motion. Resistance to the motion of a body through a fluid such as air derives from the fact that the body must move the fluid out of its way. The fluid particles are accelerated as the forward moving body collides with them opposing the motion of the body and robbing it of some of its energy. The drag is a function of the density of the fluid, and the area and velocity of the body propelled therethrough. The effect of the drag is to modify the theoretical vacuum trajectory so that the projectile falls short of the impact point it would have reached had it traveled in a vacuum.
A number of highly complex aerodynamic properties are operating when an axially symmetrical projectile is propelled out of a weapon. The most notable ones, drag, pitching moment, damping in pitch, and lift forces are usually the most important ones acting on the projectile. Other forces may also be present. These forces include rolling moments, that is moments tending to spin or retard the spin of the projectile about a longitudinal axis, pitching and yawing moments induced by deflected control surfaces, and magnus forces and magnus moments, that is moments about the pitch and yaw axes due to rotation about the roll axis.
The effect of drag and these other various forces on small projectiles, such as that utilized in a double aught (00) buck shotgun round tends to inhibit the round's hardened target penetration capability. Moreover, the ability to propel the projectile accurately at a preselected target is determined, to some degree upon the firearm's ability to stabilize the projectile in flight.
In order to stabilize the projectile in flight, the projectile is frequently spun about its longitudinal axis. The resulting gyroscopic stabilization keeps the projectile from tumbling and maintains the proper orientation in flight to keep drag at a minimum. The spin of a projectile is imparted by the rifling of the gun barrel. While the spin does tend to stabilize the orientation, in practice, the spin axis will precess so that the nose of the projectile follows a spiral path. Some further problems are introduced by spinning the projectile inasmuch as the spin, in stabilizing the orientation of the projectile along the original trajectory, causes the projectile to arrive at the point of impact at an undesirable inclination. This further inhibits the ability of the projectile to penetrate the preselected target.
Therefore, it has long been known that it would be desirable to have a projectile delivery apparatus which can be fired accurately from a conventionally designed shotgun and which is adapted to traverse the distance from the shotgun to the target while retaining the launch weight of the projectile intact, and more particularly a projectile delivery apparatus wherein the projectile is released when it engages a preselected target in a manner imparting improved penetration characteristics.